An engine intake-air cleaner apparatus is incorporated in an intake-air system of an engine in order to remove dust from intake-air and to reduce noise of intake-air.
There exists a conventional air-cleaner apparatus adapted as an air-filter apparatus to be removably fitted in an air-cleaner casing which is attached to an air-cleaner conduit. In this air-filter apparatus, a filter support member such as a net or the like is stretched in a filter attaching frame of an outer structural member which is held in the air-filter casing so as to support an air-cleaner filter with the use of the filter support member.
There exists another air-filter apparatus which is attached directly to the intake-air port of an air cleaner casing. In this air-filter apparatus, a filter support member such as an inner net is stretched in a filter attaching frame of an outer structural member such as a funnel attached to an air-cleaner conduit, and an air-cleaner filter is supported with the use of the filter support member.
In conventional air-filter apparatuses for an air-cleaner apparatus, although the filter is held by any means in the filter attaching frame of the outer frame structure member, the filter is merely set and held on the filter support member.
Further, in the conventional air-filter apparatuses, the filter support member is generally formed of hard metal materials such as stainless steel wires or a perforated stainless steel sheet.
However, conventional air-filter apparatuses have several disadvantages.
First, the filter support member repeatedly knocks the filter which is vibrated by pulsation of the intake-air in an engine so as to cause occurrence of a dust beat phenomenon by the filter. The dust beat phenomenon causes, in turn, dust caught on the inlet side part of the outer surface of the filter to gradually enter the inside of the filter, and is finally sucked into the engine from the outlet of the filter, resulting in the lowering of the dust collecting effect.
Second, the filter which is vibrated by pulsation of the intake-air in the engine and the filter support member made of hard metal materials repeatedly beat each other for a long time. As a result, the filter support member tends to break at the proximal part thereof which is attached to the outer frame structural member, so as to deteriorate the filtering function.
In addition, since the filter support member is made of hard metal materials, it bumps upon another part so as to possibly cause a damage such as bending or the like during physical distribution, and installation.
One object of the present invention therefore is to provide an engine intake-air filter apparatus which can prevent a filter from causing occurrence of the dust beating phenomenon.
Another object of the present invention is to provide an engine intake-air filter apparatus which prevents a filter from causing occurrence of a dust beating phenomenon, and which prevents damage to the filter during physical distribution, installation or usage of the filter apparatus.
One example of conventional air-cleaner apparatuses will be hereinbelow explained with reference to FIG. 12 illustrating an air-filter apparatus 1 attached directly to the intake-air port of an air-cleaner apparatus in which a flared opening of a funnel 2 is covered with an inner net 3 and an outer net 4 between which an air-cleaner filter 5 having a two-layer structure is laid.
The end parts of the inner net 3 are fixed to a flat part 6 of a funnel 2 while the end parts of the outer net 4 are removably secured to the end parts of the flat part 6. Further, each of these inner and outer nets 3, 4 is originally a rectangular net which is formed into a substantially semi-spherical shape. Further, an air-cleaner filter 5 is a wet-type filter which is impregnated with oil (having a coefficient of viscosity of 3 to 5 pa.s) in order to enhance the dust collecting effect.
However, in the air-filter apparatus 1 shown in FIG. 12, the inner net 3 and the outer net 4 are laid respectively over the front and rear surfaces of the filter 5, and accordingly, the intake-air opening area of the filter 5 is decreased so that the intake-air resistance possibly increases.
Another object of the present invention is to provide an air-cleaner filter which reduces the intake-air resistance so as to enhance the output power of an engine.
In the conventional filter apparatus 1, it is desirable to increase the flared opening of the funnel 2 in order to enhance the intake-air efficiency.
However, if the size of the funnel is increased, the air-filter apparatus 1 requires a larger-size which is unpreferable for an air-filter apparatus adapted to be located in a limited space.
Further, since the outer net 4 is a rectangular net which is formed into a substantially spherical shape, a curved part thereof is deformed, that is, its rectangular shape is deformed into a diamond-like shape or the like, and more specifically, each of the comers thereof is greatly deformed. This deformation hinders the flow of the intake-air, and accordingly, the intake-air efficiency is possibly lowered.
Further, since the air-cleaner filter 5 is impregnated with oil having a small coefficient of viscosity, in case the size of pores in porous resin (such as polyurethane resin) which forms the air-cleaner filter is large, the impregnation of oil would be insufficient. Accordingly, the air-cleaner filter 5 is made of porous resin which is impregnated with the oil, resulting in increased flow-passage resistance of the air-cleaner filter 5. In view of this point, the intake-air efficiency is lowered.
An object of the present invention is to provide an air-cleaner apparatus which can enhance the intake-air efficiency without increasing the size of the air-cleaner apparatus.